release: activate pippit-video 0.3.0

[superche]

Registry artifact was re-downloaded and verified before this exact-version marketplace activation.

Validation:

• protected release verification completed through official registry artifact comparison, install, and launcher smoke
• npm package: @pippit-bridge/mcp-server@0.3.0
• npm shasum: cd8f5566b71e2b3659166c0639594537a2fe26c3
• npm run check:plugin-version
• npm run check:plugin-contract

This PR changes only .agents/plugins/marketplace.json from 0.2.13 to 0.3.0.